Tetradecyldimethylbenzyl ammonium salt（TDMBA） cations were intercalated into sodium montmorillonite（Na-MMT） by an ion exchange reaction. The resulting TDMBA-MMT was characterized by Fourier-transform infrared spectroscopy（FTIR）, thermogravimetric analysis（TGA）, and X-ray diffraction（XRD）. Moreover, the antibacterial activity and water-resistance of TDMBA-MMT were investigated. The results show that TDMBA cations are intercalated into the Na-MMT. The onset temperature of decomposition of TDMBA cations in TDMBA-MMT is raised about 60 ℃ higher than that of tetradecyldimethylbenzyl ammonium chloride（TDMBACl）, and the d（001） spacing enlarged from 1.23 nm to 2.10 nm. 0.1 mg/mL TDMBA-MMT is fully enough to kill all the Staphylococci aureus（S, aureus） and more than 99.99% of the Escherichia coli（E, coli） in a sample solution within 6.0 h touch, and the TDMBA-MMT also shows long acting properties.
The biological effect of cerium nitrate on the outer membrane(OM) of Escherichia coli(E.coli) cell was studied,and the antim-icrobial mechanism of rare earth elements was explored.The antimicrobial effect of cerium nitrate on E.coli cell was valued by plate count method,and the morphology change of E.coli cell was observed with scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results showed that the E.coli cell suspension was flocculated when the concentration of Ce(NO3)3?6H2O...
Zinc and cerium carried zirconium phosphates （Zn-Ce/ZrPs） were prepared by exchanging zinc and cerium cations into sodium zirconium phosphate （NaZrP） through the ion-exchange method and characterized by X-ray diffraction（XRD）, energy dispersive X-ray spectroscopy （EDX） and scanning electron microscopy （SEM）. Furthermore, the specific surface area, zeta potential and antibacterial activity were tested. The results showed that Zn-Ce/ZrPs were with hexagonal crystal system, and the surface area of Zn-Ce/ZrPs increased much more than that of NaZrP. Zn-Ce/ZrPs showed obvious synergetic antibacterial effect, and have the potential to be used as antibacterial agents in environmental control.
This study aimed to delineate the antibacterial mechanism of rare-earth ion Ce3＋ to the target organism Escherichia coil cell, and the most important purpose was to identify its biological effect of increasing the E. coli cell membrane permeability. The antibacterial activi- ties of Ce3＋ to E. coli cells were tested, and then the permeability of outer membrane （OM） and inner membrane （IM） were studied by N-phenyl-l-naphthylamine （NPN） and o-nitrophenyl-β-D-galactopyranoside （ONPG） methods separately. Through these experiments we concluded that the E. coli cells grown to log phage were more sensitive to Ce3＋ than the ones not at this stage; the structure of membrane was destroyed and the permeability of both OM and IM was obviously increased by Ce3＋; there should be certain interactions between Ce3＋ and some proteins inside the cell, which impeded the physiological activities of bacteria.
Zn-montmorillonites（Zn-MMTs） as antibacterial compounds were prepared by an ion-exchange reaction. The reaction time, initial pH value and molar ratios of CEC influencing zinc content in Zn-MMTs were investigated, and Zn-MMTs were characterized by means of EDX, XRD, XPS, and SEM. The results of bacterial growth tests were confirmed by determination of the minimum inhibition concentrations （MICs） and minimum bactericidal concentrations （MBCs）. The experimental results show that the zinc is confirmed as bivalent zinc state, the d001 basal spacing of Zn-MMTs is enlarged with the enhancement of the zinc content, and the particles of Zn-MMTs are formed with irregular shape. Moreover, the antibacterial activity of Zn-MMTs increases with increasing the zinc content, and Zn-MMT-3 containing 6.76 mass% of zinc exhibits optimum antibacterial activity against Escherichia coli and Staphylococcus aureus.
A series of zinc ions or/and cerium ions co-doped a-zirconium phosphate （Zn-Ce@ZrPs） were prepared. The novel Zn-Ce@ZrPs were characterized and the antibacterial activity on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were tested. The results showed that zinc ions （Zn2＋） or/and cerium ions （Ce3＋） were combined with ZrP, and the Ce3＋ was adsorbed on the surface of ZrP through hydrogen bonds, while Zn2＋ intercalated into the interlayer of ZrP. Zn-Ce@ZrPs showed excellent synergistic antibacterial activity. When Zn2＋/Ce3＋ atomic ratio was 0.6, the Zn-Ce@ZrP3 showed the highest synergistic antibacterial efficiency, suggesting great potential ap- plication as antibacterial agents in microbial control.
